biped joints position

Hi everyone,
I'd like to know if is there a script that allows me to do this:

I've a 3d character model skinned with a hierarchy of dummy objects that control character deformation.

I'd like to animate the character using the Biped module so I thought to make dummy objects liked to the biped joints, and finally animate just the biped skeleton.

Obviously I can't adapt the dummy hierarchy to the biped skeleton, 'cause this deform my character.

I'd like to to the invers: adapt the biped skeleton to the dummy hierarchy, is there a way to set manually XYZ value for each biped skeleton part?

Thank you in advance.